The present invention relates to an improvement of a connector engagement device which is mainly used for mutual connection of connection terminal sets having a large number of connection terminals, such as a car wire harness, so that mutual connection/locking of a pair of female and male connectors is performed using a small insertion/removal force by leverage of an operation cam lever.
As a general connector engagement device for performing connection using a small insertion/removal force by using an operation cam lever, for example, there is a configuration as disclosed in Japanese Utility Model Unexamined Publication No. Hei. 4-29179. Hereupon, the outline of the conventional configuration and the state of the engaging operation are shown in FIGS. 5 through 8 successively.
In the configuration shown in each of FIGS. 5 through 8, the conventional connector engagement device for performing connection using a small insertion/removal force comprises a pair of female and male connectors 51 and 61, and an operation cam lever 71 rotatably mounted on the female connector 51.
More in detail, the female connector 51 receives a set of connection terminals (not shown) so as to face the connection opening end portion side in a housing portion 52 and has a fulcrum axis pin 53 formed so as to project on the connection end portion on each of two opposite sides (only one side is shown in the drawings) and at a predetermined position on the connection-direction center line s equivalent to a substantially middle portion of the effective overall width w.sub.1 of the female connector 51.
Similarly to the female connector 51, the male connector 61 receives a set of connection terminals (not shown) to be connected to the set of connection terminals of the female connector 51 so that the set of connection terminals face the connection opening end portion side of a housing portion 62 and has an engagement pin 63 formed to project on each of two opposite sides (only one side is shown in the drawings) of the male connector 61 at the connection end portion side thereof so as to be located in a predetermined position on the common connection-direction center line s equivalent to the substantially middle portion of the effective overall width w.sub.2 of the male connector 61.
Further, the operation cam lever 71 is rotatably pivotally supported on the female connector 51 so as to rise over the pair of fulcrum axis pins 53 on the opposite sides of the female connector 51. The operation cam lever 71 is provided with cam grooves 72 which are formed so that the engagement pins 63 can be pulled toward the female connector 51 side in the condition that the engagement pins 63 of the male connector 61 are received in the cam grooves 72 respectively of the cam operation lever 71.
Making the pivotal point of each fulcrum axis pin 53 of the female connector 51 a center, each of the cam grooves 72 of the operation cam lever 71 is composed of: a lead-in opening portion 72a which can receive, without any stress, a corresponding one of the engagement pins 63 of the male connector 61 in an open position of the operation cam lever 71; a guide cam groove portion 72b connected to the lead-in opening portion 72a and extended so as to gradually pull the engagement pin 63 toward the pivotal point; and a locking groove portion 72c connected to the guide cam groove portion 72b so as to lock and hold the engagement pin 63.
Accordingly, in the case of the aforementioned conventional connector engagement device, when the set of connection terminals of the male connector 61 are first temporarily connected to the set of connection terminals of the female connector 51 by shallow insertion of the male connector 61 into the female connector 51 in a state (FIG. 5) in which the connection opening end portion of the male connector 61 is put so as to face the connection opening end portion of the female connector 51, the engagement pins 63 of the male connector 61 are led into the lead-in opening portions 72a of the operation cam lever 71 which are held in the open position in the state that the cam lever 71 is pivotally supported on the female connector 51 (FIG. 6).
When the operation cam lever 71 on the female connector 51 side is then rotated around the pivot point of the fulcrum axis pins 53 in the direction to the engagement position as indicated by the arrow from the connecting operation initiating end a side to the connecting operation terminating end b side in the aforementioned condition, the engagement pins 63 of the male connector 61 led in the lead-in opening portions 72a of the operation cam lever 71 are guided by the guide cam grooves 72b which are formed so as to be made closer gradually to the pivot points, while the engagement pins 63 are in slide contact with the groove surfaces of the guide cam grooves 72b opposite to the fulcrum axis pins 53. As a result, the engagement pins 63 are pulled to the engagement position gradually by a relatively small rotational-direction operating force because of the leverage, around the pivot points, of the guide cam groove portions 72b, so that the set of connection terminals of the male connector 61 are connected gradually deeply to the set of connection terminals of the female connector 51. When the engagement pins 63 reach the respective terminal side of the guide cam groove portions 72b, the two sets of connection terminals are connected to each other (FIG. 7).
When the rotating operation of the operation cam lever 71 is further continued, the engagement pins 63 are received respectively in the locking groove portions 72c to thereby lock the state of connection of the set of connection terminals of the male connector 61 in the set of connection terminals of the female connector 51. Thus, the complete connection is finished (FIG. 8). In this connection completion state, the engagement pins 63 of the male connector 61 are moved toward the female connector 51 side to a predetermined distance on the center line s in the direction of engagement and connection which passes through the pivot point of the female connector 51, and held there.
Incidentally, the locked connection state can be unlocked easily by an operation reverse to the aforementioned operation.
In the aforementioned conventional connector engagement device, however, the pair of engagement pins 63 projected on the respective connection-direction center lines s on opposite sides of the male connector 61 are pulled toward the female connector 51 side through the rotational operation of the operation cam lever from the connecting operation initiating end a side to the connecting operation terminating end b side, by the pair of guide cam grooves 72b formed respectively in the opposite sides of the operation cam lever 71 which is mounted on the female connector 51 so as to be pivotally supported by the fulcrum axis pins 53 on the respective connection-direction center lines s so that the overall mutual connection of the set of connection terminals of the male connector 61 to the set of connection terminals of the female connector 51 is performed by a small insertion/removal force effected by the leverage. Thus, the following problems occur.
That is, when the state of connection of the set of connection terminals of the male connector 61 into the set of connection terminals of the female connector 51 is seen on the whole, the operation cam lever 71 becomes such that upon completion of the connecting operation, the connection operating force B of the operation cam lever 71 on the connecting operation terminating end b side is inevitably stronger than the connection operating force A on the connecting operation initiating end a side so that the connection operating forces have the relation A &lt;B, by the operation force of the operation cam lever 71 given unilaterally from the connecting operation terminating end b side to the engagement pins 63 in the later stage of the connecting operation.
Accordingly, if the connection operating forces applied at the time of the mutual connection of the two sets of connection terminals of the female and male connectors 51 and 61 are in such a relation A &lt;B so as to be unbalanced between the connecting operation initiating end a side and the connecting operation terminating end b side, the connecting operation initiating end a side subjected to the connection operating force A weaker than the connection operating force B is apt to be floated up in the direction of non-connection because of the connection operating force B given to the connection terminating end b side. Accordingly, the connecting operation initiating end a side is apt to become unstable, resulting in so-called oblique fitting in which the connection per se is not performed correctly along the connection-direction center lines s to thereby impede the smoothness of the operation. Consequently, there arises a problem that lowering of reliability of the mutual connection is brought about.